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Chemical Fixation of Carbon Dioxide Using Solid Catalysts in Supercritical Carbon Dioxide

在超临界二氧化碳中使用固体催化剂化学固定二氧化碳

基本信息

批准号：
15560664
负责人：
FUJITA Shin-ichiro
金额：
$ 2.11万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560664/
关键词：
Supercritical carbon dioxide Chemical fixation of carbon dioxide Solid base catalyst Cyclic carbonate Dimethyl carbonate Cyclic urethane Cyclic urea 化学的固定化固体塩基触媒エポキシドイオン性液体カーボネイトエポキシ

项目摘要

Chemical fixation of carbon dioxide (CO_2) is an important issue from the viewpoint of green chemistry. On the other hand, supercritical CO_2 (scCO_2) is an easily recyclable and environmentally benign solvent and, furthermore it can eliminate the interface between gas and liquid phases. So, the use of scCO_2 as both the solvent and the substrate may give efficient reaction systems for the chemical fixation of CO_2. The aims of the present study are to investigate the characteristics of chemical fixation of CO_2 using solid catalysts in scCO_2 and to search catalysts active for such the reaction systems.1.SYNTHESIS OF CYCLIC CARBONATE: Several smectite catalysts were prepared and used for the reaction of CO_2 and propylene oxide. It was found that strongly basic sites whose amount depends on the alkali atoms incorporated are significant for the reaction. High CO_2 pressures are not needed to obtain high yields. Bi-functional catalyst systems of Lewis acid (ZnBr_2) and Lewis base (imida … More zolium salts, quaternary ammonium salts) were found to be very active. They can produce styrene carbonate under mild conditions even from styrene oxide that has very low reactivity for the reaction. The influence of CO_2 pressure is different by the catalyst systems.2.ONE-POT SYNTHESIS OF DIMETHYL CARBONATE (DMC) : It was found that smectite catalysts can be used for the reaction of CO_2, propylene oxide and methanol to produce DMC. Strongly basic sites are significant also for this reaction. They retards the side reaction, methanolysis of the epoxide.3.SYNTHSIS OF CYCLIC URETHANE AND UREA : CO_2 cycloaddition reactions with diamine and aminoalcohol were carried out without catalysts. Aliphatic cyclic urea was produced in excellent yields ; however, the yields of aromatic cyclic urea and both aliphatic and aromatic cyclic urethane were low. So, several solid catalysts and ionic liquids were tested for the synthesis of cyclic urethane. It was found imidazolium salts can catalyze this reaction.4.OXIDATIVE CARBOXYLATION OF STYRENE : Tetrabutyl ammonium bromide (TBAB) was found to be a good catalyst for the production of styrene carbonate (SC) from styrene, CO_2 and organic peroxide in one-pot. It gave better SC yields than those reported so far. Combination of TBAB-ZnBr_2-Au/SiO_2 was also a good catalyst system. It could reduce the reaction time compared with TBAB alone. The SC yield was slightly improved by this tri-functional system. Less

从绿色化学的观点来看，二氧化碳的化学固定是一个重要的问题。另一方面，超临界CO_2(SCCO_2)是一种易回收、环境友好的溶剂，而且可以消除气液两相界面。因此，使用SCCO_2作为溶剂和底物，可以为CO_2的化学固定提供有效的反应体系。本研究的目的是研究固体催化剂在SCCO_2中化学固定CO_2的特性，并寻找具有这种反应活性的催化剂。1.环碳酸酯的合成：制备了几种蒙脱石催化剂，并用于CO_2和环氧丙烷的反应。研究发现，强碱性中心对反应具有重要意义，其数量与所结合的碱原子有关。获得高产率不需要较高的CO_2压力。路易斯酸(ZnBr2)和路易斯碱(IMIDA…)双功能催化体系更多的唑盐，季铵盐)被发现是非常活跃的。他们可以在温和的条件下生产碳酸苯酯，即使是从反应活性非常低的环氧苯乙烷。不同的催化剂体系对CO_2压力的影响不同。2.碳酸二甲酯(DMC)的一锅合成法：发现蒙脱石催化剂可用于CO_2、环氧丙烷和甲醇合成碳酸二甲酯的反应。强碱性部位对该反应也很重要。3.环氨基甲酸酯和尿素的合成：CO_2与二胺和氨基醇的环加成反应在无催化剂的情况下进行。脂肪族环状尿素的产率很高，但芳香族环状尿素和脂肪族和芳香族环氨基甲酸酯的产率都很低。为此，我们考察了几种固体催化剂和离子液体对环状氨基甲酸酯合成的影响。4.苯乙烯的氧化羧化反应：发现四丁基溴化铵(TBAB)是一锅法合成碳酸苯乙烯(SC)的良好催化剂。它提供了比迄今报道的更好的SC收益率。TbAB-ZnBr2-Au/SiO_2复合体系也是较好的催化剂体系。与单用TBAB相比，可缩短反应时间。该三效体系对超临界流体的产率略有提高。较少